Polymeric release materials are known to be used in release layers in release articles (e.g., release liners) and adhesive articles (e.g., adhesive tapes) in order to provide a surface from which an adhesive can be easily and cleanly removed. For example, it is known to apply a polymeric release material to the back surface of an adhesive tape (e.g., a box sealing tape) in order to allow the tape to be provided in roll form and to be easily and conveniently dispensed by unwinding the roll.
One commonly used method of forming a release layer is to coat the release material from a solvent-based solution onto a substrate. After the solution has been applied to the substrate, the solvent is evaporated leaving behind a relatively uniform coating of the release material.
As environmental regulations tighten, release materials that can be processed using solvent-free processes are more desirable. One method by which release materials can be formed into layers without solvent emission is by extrusion. In an extrusion process, a 100% solids release material is heated to a melt and is forced through an extrusion die under pressure to form a release layer. The few examples of extrudable 100% solids release compositions generally include, in addition to the polymeric release material, one or more other polymeric materials which act as carriers for the release agent.
For efficient manufacturing, it is generally preferred that the various components making up the release material composition can be directly fed into an extruder as separate materials. If this is not possible, then the various components must first be pre-blended in a separate process, and the pre-blended material pelletized to provide a homogeneous feed material for the extruder. This pre-blending and pelletizing adds additional cost to the final product, which is not desirable.
In view of the foregoing, release compositions that can be fed directly into an extruder without pre-blending of the components making up the release composition are desirable.